• Question: Why do farts smell

    Asked by Ella and Kyi Nue to Miriam, Kathryn, David on 12 Nov 2018.
    • Photo: Kathryn Coldham

      Kathryn Coldham answered on 12 Nov 2018:


      Fantastic question! I believe it’s due to farts containing a gas called methane, causing for it to smell. But farts aren’t really my field I’m afraid so I don’t know the exact answer 🙂

    • Photo: David Ho

      David Ho answered on 12 Nov 2018:


      I don’t mean to barge in on Kathryn’s answer, but, although farts do contain methane, methane is actually odourless! Methane is the gas that you get in gas taps in science labs, and the reason why that smells is a chemical called mercaptan that is added to the gas, because otherwise nobody would know if there was a gas leak!

      According to this Wikipedia article the chemicals that make farts smell make up less than 1% of the actual fart — and they are mainly sulfur-containing compounds like hydrogen sulfide, a chemical that’s also responsible for the smell of rotten eggs (kind of makes sense…) https://en.wikipedia.org/wiki/Flatulence#Production,_composition,_and_smell

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